[dpdk-dev] [PATCH v2 1/4] ring: future proof flag settings

[Stephen Hemminger <stephen@networkplumber.org>]

All API's should check that they support the flag values passed.
These checks ensure that the extra bits can safely be used
without risk of ABI breakage.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 lib/librte_ring/rte_ring.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/lib/librte_ring/rte_ring.c b/lib/librte_ring/rte_ring.c
index ebe5ccf0de68..70685121581f 100644
--- a/lib/librte_ring/rte_ring.c
+++ b/lib/librte_ring/rte_ring.c
@@ -42,6 +42,9 @@ static struct rte_tailq_elem rte_ring_tailq = {
 };
 EAL_REGISTER_TAILQ(rte_ring_tailq)
 
+/* mask of all valid flag values to ring_create() */
+#define RING_F_MASK	0x007F
+
 /* true if x is a power of 2 */
 #define POWEROF2(x) ((((x)-1) & (x)) == 0)
 
@@ -197,6 +200,13 @@ rte_ring_init(struct rte_ring *r, const char *name, unsigned count,
 	RTE_BUILD_BUG_ON(offsetof(struct rte_ring_headtail, tail) !=
 		offsetof(struct rte_ring_rts_headtail, tail.val.pos));
 
+	/* future proof flags, only allow supported values */
+	if (flags & ~RING_F_MASK) {
+		RTE_LOG(ERR, RING,
+			"Unsupported flags requested %#x\n", flags);
+		return -EINVAL;
+	}
+
 	/* init the ring structure */
 	memset(r, 0, sizeof(*r));
 	ret = strlcpy(r->name, name, sizeof(r->name));
-- 
2.20.1